Here's a fascinating bit of film history: one of the most incredible moments in movie history wasn't in a movie at all but just a test shot for Jurassic Park. It's that test footage—of a T-Rex walking—that changed movies forever. It's that scene—simply called the Dinosaur Skin Test—that made filmmakers realize how powerful CGI was and how they could truly create whatever they wanted in movies.

Before that test sequence, Jurassic Park was going to use a combination of stop motion animation and practical effects to create the dinosaurs. After seeing a computer generated T-Rex walk so naturally though, it became clear that the movie would have to be done in CGI and practical effects. That decision to make dinosaurs digitally ushered in the use (and sometimes overuse) of CGI in movies we see today.